LOS ALAMOS, New Mexico (AP) — At Los Alamos National Laboratory, a seven-year, $213 million upgrade to the security system that protects the lab’s most sensitive nuclear bomb-making facilities doesn’t work. Those facilities, which sit atop a fault line for potential earthquakes, remain susceptible to collapse and dangerous radiation releases, despite millions more spent on improvement plans.

In Tennessee, the price tag for a new uranium processing facility has grown nearly sevenfold in eight years, to beyond $6 billion, because of problems that include a redesign to raise the roof.

And the estimated cost of an effort to refurbish 400 of the country’s B61 bombs has grown from $1.5 billion to $10 billion.

Virtually every major project under the National Nuclear Security Administration’s oversight is behind schedule and over budget — the result, watchdogs and government auditors say, of years of lax accountability for the agency responsible for maintaining the nation’s nuclear stockpile.

The NNSA has racked up $16 billion in cost overruns on 10 major projects that are a combined 38 years behind schedule, the U.S. Government Accountability Office reports. Other projects have been cancelled or suspended, despite hundreds of millions of dollars already spent, because they grew too bloated.

Advocates say spending increases are necessary to keep the nation’s nuclear arsenal operating and safe, and to continue cutting-edge research at the nation’s nuclear labs. But critics say the nuclear program — run largely by private contractors and overseen by the NNSA, an arm of the U.S. Energy Department — has turned into a massive jobs program with duplicative functions.

U.S. Sen. Claire McCaskill, chairwoman of the Senate Homeland Security financial and contracting oversight subcommittee, said a key problem is the Energy Department’s reliance on private contractors to carry out its mission. The DOE has fewer than 16,000 employees and more than 92,000 contractors.

“Unfortunately for the taxpayer … cost overruns, scheduled delays and technical failures are the rule, not the exception,” said McCaskill.

The retired head of one of those contractors, former Lockheed Martin CEO Norman Augustine, told Congress this spring that the absence of day-to-day accountability and an ineffectual structure at the NNSA pose a national security risk.

DOE and NNSA officials agree there are problems. Energy Secretary Ernest Moniz said this month that addressing the cost overruns and the embarrassing security breaches at some facilities is a top priority. A congressionally appointed panel, co-chaired by Augustine, recently began studying a potential overhaul of the NNSA.

Members of the panel Augustine co-chairs, made up of retired military officials, former lab officials and former members of Congress, declined requests for interviews.

Moniz acknowledged some projects had seen “substantial cost overruns.”

An NNSA spokesman referred The Associated Press to congressional testimony by the agency’s project and acquisitions manager, Bob Raines, who said projects completed in the last two years had met cost goals and finished under budget.

“We are making progress,” Raines testified in March before a House of Representatives subcommittee.

The nuclear labs are getting renewed scrutiny after an incident last year in Tennessee. An elderly nun and two other protesters cut through security fences, hung banners and crime-scene tape and hammered off a small chunk of a building inside the complex that is the nation’s central repository for bomb-grade uranium.

The problems have resulted in renewed scrutiny and changes in leadership at the NNSA over the past year. In August, President Barack Obama nominated retired Air Force Lt. Gen. Frank Klotz as its next head. He’s awaiting Senate confirmation.